Comparison of biopolymer scaffolds for the fabrication of skin substitutes in a porcine wound model.

This study compared three acellular scaffolds as templates for the fabrication of skin substitutes. A collagen-glycosaminoglycan (C-GAG), a biodegradable polyurethane foam (PUR) and a hybrid combination (PUR/C-GAG) were investigated. Scaffolds were prepared for cell inoculation.

Advances in Skin Tissue Bioengineering and the Challenges of Clinical Translation.

Skin tissue bioengineering is an emerging field that brings together interdisciplinary teams to promote successful translation to clinical care. Extensive deep tissue injuries, such as large burns and other major skin loss conditions, are medical indications where bioengineered skin substitutes (that restore both dermal and epidermal tissues) are being studied as alternatives. These may not only reduce mortality but also lessen morbidity to improve quality of life and functional outcome compared with the current standards of care.

Scale-up of a Composite Cultured Skin Using a Novel Bioreactor Device in a Porcine Wound Model.

Extensive deep-burn management with a two-stage strategy can reduce reliance on skin autografts; a biodegradable polyurethane scaffold to actively temporize the wound and later an autologous composite cultured skin (CCS) for definitive closure. The materials fulfilling each stage have undergone in vitro and in vivo pretesting in "small" large animal wounds. For humans, producing multiple, large CCSs requires a specialized bioreactor.

A Novel Biodegradable Polyurethane Matrix for Auricular Cartilage Repair: An In Vitro and In Vivo Study.

Auricular reconstruction poses a challenge for reconstructive and burns surgeons. Techniques involving cartilage tissue engineering have shown potential in recent years. A biodegradable polyurethane matrix developed for dermal reconstruction offers an alternative to autologous, allogeneic, or xenogeneic biologicals for cartilage reconstruction.

Optimization of a polyurethane dermal matrix and experience with a polymer-based cultured composite skin.

The aims were to (1) describe the in vivo studies leading to an optimized model of the biodegradable temporizing matrix (BTM), (2) describe our efforts in effecting closure over this optimized matrix after integration with a cultured composite skin (CCS), and (3) reexamine the ability of the CCS to definitively close fresh wounds (without BTM). Foam scaffolds of biodegradable polyurethane were created to allow in vivo tissue ingrowth or in vitro co-culture. Using the porcine surgical model, multiple BTM optimization studies took place before the BTM-CCS main study was conducted.

"Take" of a polymer-based autologous cultured composite "skin" on an integrated temporizing dermal matrix: proof of concept.

This study aimed to investigate the ability of an autologous cultured composite skin (CCS) to close similar biodegradable temporizing matrix (BTM)-integrated wounds, and its effectiveness in healing fresh full-thickness wounds after the failure of cultured epithelial autograft in its two forms (sheets and suspensions) to epithelialize over an integrated polymer BTM. Using a porcine model, autologous split-skin grafts were harvested three of four dorsal 8 × 8 cm treatment sites. These three sites were subsequently converted to full-thickness wounds and BTMs were implanted.

Split skin graft application over an integrating, biodegradable temporizing polymer matrix: immediate and delayed.

The objective of this study is to further investigate the NovoSorb™ biodegradable polyurethane in generating dermal scaffolds; to perform a pilot study comparing the previously used spun mat against a recently developed NovoSorb™ foam, ascertaining the optimum structure of the matrix; and to evaluate the successful matrix as an immediate adjunct to split skin grafting and as a temporizing matrix in a prospective six-pig study. A pilot study comparing a previously investigated form of the polymer (spun mat) against a new structural form, a foam, was performed. This was followed by a six-pig study of the foam matrix with three treatment arms-autologous split skin graft alone, polymer foam with immediate engraftment, and polymer foam with delayed engraftment.

Comparison of a sealed, polymer foam biodegradable temporizing matrix against Integra® dermal regeneration template in a porcine wound model.

The aim of this study is to develop and optimize the first stage of a proposed two-stage skin graft replacement strategy. This entails creation of a material that can be applied immediately after burn excision to "temporize" the wound bed, become integrated as a "neodermis," resist contraction and infection, and provide the grounding for the second stage (an autologous, cultured composite skin). Four 8 × 8 cm wounds were generated in six pigs to assess and compare wound contraction using Integra® dermal regeneration template, a biodegradable temporizing polymer matrix (sealed and unsealed), and a secondary intention wound.

A comparison of wound area measurement techniques: visitrak versus photography.

Objective: To investigate whether a cheap, fast, easy, and widely available photographic method is an accurate alternative to Visitrak when measuring wound area in cases where a non-wound-contact method is desirable.

Methods: The areas of 40 surgically created wounds on porcine models were measured using 2 techniques-Visitrak and photography combined with ImageJ. The wounds were photographed with a ruler included in the photographic frame to allow ImageJ calibration.

Real-time demonstration of split skin graft inosculation and integra dermal matrix neovascularization using confocal laser scanning microscopy.

Objectives: During the first 48 hours after placement, an autograft "drinks" nutrients and dissolved oxygen from fluid exuding from the underlying recipient bed ("plasmatic imbibition"). The theory of inosculation (that skin grafts subsequently obtain nourishment via blood vessel "anastomosis" between new vessels invading from the wound bed and existing graft vessels) was hotly debated from the late 19th to mid-20th century. This study aimed to noninvasively observe blood flow in split skin grafts and Integra dermal regeneration matrix to provide further proof of inosculation and to contrast the structure of vascularization in both materials, reflecting mechanism.

Evaluation of a novel biodegradable polymer for the generation of a dermal matrix.

Dermal skin substitutes can be used to overcome the immediate problem of donor site shortage in the treatment of major skin loss conditions, such as burn injury. In this study, the biocompatibility, safety, and potential of three variants of NovoSorb (a family of novel biodegradable polyurethanes) as dermal scaffolds were determined in a series of in vitro and in vivo systems. All three polymers exhibited minimal cytotoxic effects on human skin cells, allowing keratinocytes, dermal fibroblasts, and microvascular endothelial cells to grow normally in coculture.

Noncultured keratinocyte/melanocyte cosuspension: effect on reepithelialization and repigmentation--a randomized, placebo-controlled study.

Randomized controlled trials in the literature investigating the efficacy of noncultured keratinocyte/melanocyte suspensions are scarce; however, the advocates of such techniques press the value of their application based largely on case studies and anecdote. Caucasian patients with burn hypopigmentation seldom request cosmetic revision making worthwhile clinical trials difficult so that informal case treatments with new therapies generate anecdotal results. A randomized, placebo-controlled trial was carried out to evaluate whether cosuspensions of noncultured skin cells are capable of (1) decreasing the time to reepithelialization and (2) reestablishing pigmentation in vitiligo leukoderma following epidermal/superficial dermal ablation (in the knowledge that a positive result would make the technique likely to be successful in burn hypopigmentation).

Nipple-areolar pigmentation: histology and potential for reconstitution in breast reconstruction.

The makeup of nipple-areolar skin, in terms of its melanin and melanocyte content has not previously been established. This histological information is required if pigmentation of the reconstructed nipple-areola is to be successful in post-mastectomy breast reconstruction. We describe examination of 200 parallel sections of nipple-areolar skin of 20 women using histochemical (Masson-Fontana) and immunohistochemical (Mel-5) techniques, evaluated using quantitative image analysis.